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SUMMARY:Bi nanolines on Si (001) - Dr. David Bowler\, London Centre for Na
 notechnology\, London\; Department of Physics & Astronomy\, University Col
 lege London\, and Thomas Young Centre @ UCL
DTSTART:20100219T140000Z
DTEND:20100219T150000Z
UID:TALK23164@talks.cam.ac.uk
CONTACT:spl37
DESCRIPTION:Annealing a Bi-covered Si(001) surface at around 600C leads t
 o significant Bi desorption\, but the remaining Bi forms remarkable featur
 es on the surface: nanolines which are 1.5 nm wide\, up to microns long an
 d completely without kink or defect (when fully mature). The driving force
  behind the nanoline formation is a complex subsurface reconstruction know
 n as the Haiku (it consists of 5- and 7-membered rings).\nThe Bi nanolines
 \, while remarkable\, have a wider bandgap than the Si(001) surface\; howe
 ver\, they are excellent\ncandidates for nanoline templating. Overgrowth w
 ith In leads to a wetting behaviour\, with a zigzag one dimensional III-V 
 chain forming. Recent modelling suggests that Cu will attack the Bi-Si bon
 ds\, forming extended conducting wires one atom wide (in contrast to Ag\, 
 which forms islands on the nanolines).\nRecently\, it has been shown that 
 the Bi can be removed from the nanolines\, leaving a Si-in-Si nanotemplate
 \,  which confirms the existence of the subsurface reconstruction\, and ha
 s potential to act as a different template for nanowire growth. Bi nanolin
 es can also be buried in crystalline silicon without losing their one-dime
 nsional nature. I will present details of this fascinating system drawn fr
 om extensive experimental-theoretical collaborations.
LOCATION:Kapitza Building Seminar Room\, Cavendish Laboratory\, Department
  of Physics
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